// HTMLParser Library $Name: v1_6 $ - A java-based parser for HTML
// http://sourceforge.org/projects/htmlparser
// Copyright (C) 2003 Derrick Oswald
//
// Revision Control Information
//
// $Source: /cvsroot/htmlparser/htmlparser/src/org/htmlparser/filters/HasChildFilter.java,v $
// $Author: derrickoswald $
// $Date: 2005/05/15 11:49:04 $
// $Revision: 1.5 $
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; either
// version 2.1 of the License, or (at your option) any later version.
//
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
// Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
//

package org.htmlparser.filters;

import org.htmlparser.Node;
import org.htmlparser.NodeFilter;
import org.htmlparser.tags.CompositeTag;
import org.htmlparser.util.NodeList;

/**
 * This class accepts all tags that have a child acceptable to the filter. It
 * can be set to operate recursively, that is perform a scan down through the
 * node heirarchy in a breadth first traversal looking for any descendant that
 * matches the predicate filter (which stops the search).
 */
public class HasChildFilter implements NodeFilter {
	/**
	 * The filter to apply to children.
	 */
	protected NodeFilter mChildFilter;

	/**
	 * Performs a recursive search down the node heirarchy if <code>true</code>.
	 */
	protected boolean mRecursive;

	/**
	 * Creates a new instance of a HasChildFilter. With no child filter, this
	 * would always return <code>false</code> from {@link #accept}.
	 */
	public HasChildFilter() {
		this(null);
	}

	/**
	 * Creates a new instance of HasChildFilter that accepts nodes with a direct
	 * child acceptable to the filter.
	 * 
	 * @param filter
	 *            The filter to apply to the children.
	 */
	public HasChildFilter(NodeFilter filter) {
		this(filter, false);
	}

	/**
	 * Creates a new instance of HasChildFilter that accepts nodes with a child
	 * acceptable to the filter. Of necessity, this applies only to composite
	 * tags, i.e. those that can contain other nodes, for example
	 * &lt;HTML&gt;&lt;/HTML&gt;.
	 * 
	 * @param filter
	 *            The filter to apply to children.
	 * @param recursive
	 *            If <code>true</code>, any enclosed node acceptable to the
	 *            given filter causes the node being tested to be accepted (i.e.
	 *            a recursive scan through the child nodes down the node
	 *            heirarchy is performed).
	 */
	public HasChildFilter(NodeFilter filter, boolean recursive) {
		setChildFilter(filter);
		setRecursive(recursive);
	}

	/**
	 * Get the filter used by this HasParentFilter.
	 * 
	 * @return The filter to apply to parents.
	 */
	public NodeFilter getChildFilter() {
		return (mChildFilter);
	}

	/**
	 * Set the filter for this HasParentFilter.
	 * 
	 * @param filter
	 *            The filter to apply to parents in {@link #accept}.
	 */
	public void setChildFilter(NodeFilter filter) {
		mChildFilter = filter;
	}

	/**
	 * Get the recusion setting for the filter.
	 * 
	 * @return Returns <code>true</code> if the filter is recursive up the
	 *         node heirarchy.
	 */
	public boolean getRecursive() {
		return (mRecursive);
	}

	/**
	 * Sets whether the filter is recursive or not.
	 * 
	 * @param recursive
	 *            The recursion setting for the filter.
	 */
	public void setRecursive(boolean recursive) {
		mRecursive = recursive;
	}

	/**
	 * Accept tags with children acceptable to the filter.
	 * 
	 * @param node
	 *            The node to check.
	 * @return <code>true</code> if the node has an acceptable child,
	 *         <code>false</code> otherwise.
	 */
	public boolean accept(Node node) {
		CompositeTag tag;
		NodeList children;
		boolean ret;

		ret = false;
		if (node instanceof CompositeTag) {
			tag = (CompositeTag) node;
			children = tag.getChildren();
			if (null != children) {
				for (int i = 0; !ret && i < children.size(); i++)
					if (getChildFilter().accept(children.elementAt(i)))
						ret = true;
				// do recursion after all children are checked
				// to get breadth first traversal
				if (!ret && getRecursive())
					for (int i = 0; !ret && i < children.size(); i++)
						if (accept(children.elementAt(i)))
							ret = true;
			}
		}

		return (ret);
	}
}
